Maximize button for resizable instruments

include/SubWindow.h

@@ -78,6 +78,8 @@ class LMMS_EXPORT SubWindow : public QMdiSubWindow
 	void paintEvent( QPaintEvent * pe ) override;
 	void changeEvent( QEvent * event ) override;
 
+	QPushButton* addTitleButton(const std::string & iconName, const QString & toolTip);
+
 signals:
 	void focusLost();
 

src/gui/SubWindow.cpp

@@ -58,28 +58,13 @@ SubWindow::SubWindow(QWidget *parent, Qt::WindowFlags windowFlags) :
 	m_borderColor = Qt::black;
 
 	// close, maximize and restore (after maximizing) buttons
-	m_closeBtn = new QPushButton( embed::getIconPixmap( "close" ), QString(), this );
-	m_closeBtn->resize( m_buttonSize );
-	m_closeBtn->setFocusPolicy( Qt::NoFocus );
-	m_closeBtn->setCursor( Qt::ArrowCursor );
-	m_closeBtn->setAttribute( Qt::WA_NoMousePropagation );
-	m_closeBtn->setToolTip( tr( "Close" ) );
+	m_closeBtn = addTitleButton("close", tr("Close"));
 	connect( m_closeBtn, SIGNAL(clicked(bool)), this, SLOT(close()));
 
-	m_maximizeBtn = new QPushButton( embed::getIconPixmap( "maximize" ), QString(), this );
-	m_maximizeBtn->resize( m_buttonSize );
-	m_maximizeBtn->setFocusPolicy( Qt::NoFocus );
-	m_maximizeBtn->setCursor( Qt::ArrowCursor );
-	m_maximizeBtn->setAttribute( Qt::WA_NoMousePropagation );
-	m_maximizeBtn->setToolTip( tr( "Maximize" ) );
+	m_maximizeBtn = addTitleButton("maximize", tr("Maximize"));
 	connect( m_maximizeBtn, SIGNAL(clicked(bool)), this, SLOT(showMaximized()));
 
-	m_restoreBtn = new QPushButton( embed::getIconPixmap( "restore" ), QString(), this );
-	m_restoreBtn->resize( m_buttonSize );
-	m_restoreBtn->setFocusPolicy( Qt::NoFocus );
-	m_restoreBtn->setCursor( Qt::ArrowCursor );
-	m_restoreBtn->setAttribute( Qt::WA_NoMousePropagation );
-	m_restoreBtn->setToolTip( tr( "Restore" ) );
+	m_restoreBtn = addTitleButton("restore", tr("Restore"));
 	connect( m_restoreBtn, SIGNAL(clicked(bool)), this, SLOT(showNormal()));
 
 	// QLabel for the window title and the shadow effect
@@ -94,9 +79,8 @@ SubWindow::SubWindow(QWidget *parent, Qt::WindowFlags windowFlags) :
 	m_windowTitle->setGraphicsEffect( m_shadow );
 
 	// disable the minimize button
-	setWindowFlags( Qt::SubWindow | Qt::WindowMaximizeButtonHint |
-		Qt::WindowSystemMenuHint | Qt::WindowCloseButtonHint |
-		Qt::CustomizeWindowHint );
+	setWindowFlags(this->windowFlags() & ~Qt::WindowMinimizeButtonHint);
+
 	connect( mdiArea(), SIGNAL(subWindowActivated(QMdiSubWindow*)), this, SLOT(focusChanged(QMdiSubWindow*)));
 }
 
@@ -111,12 +95,17 @@ SubWindow::SubWindow(QWidget *parent, Qt::WindowFlags windowFlags) :
  */
 void SubWindow::paintEvent( QPaintEvent * )
 {
+	// Don't paint any of the other stuff if the sub window is maximized
+	// so that only its child content is painted.
+	if (isMaximized())
+	{
+		return;
+	}
+
 	QPainter p( this );
 	QRect rect( 0, 0, width(), m_titleBarHeight );
 
-	bool isActive = mdiArea()
-			? mdiArea()->activeSubWindow() == this
-			: false;
+	const bool isActive = windowState() & Qt::WindowActive;
 
 	p.fillRect( rect, isActive ? activeColor() : p.pen().brush() );
 
@@ -295,9 +284,25 @@ void SubWindow::moveEvent( QMoveEvent * event )
  */
 void SubWindow::adjustTitleBar()
 {
+	// Don't show the title or any button if the sub window is maximized. Otherwise they
+	// might show up behind the actual maximized content of the child widget.
+	if (isMaximized())
+	{
+		m_closeBtn->hide();
+		m_maximizeBtn->hide();
+		m_restoreBtn->hide();
+		m_windowTitle->hide();
+
+		return;
+	}
+
+	// Title adjustments
+	m_windowTitle->show();
+
 	// button adjustments
 	m_maximizeBtn->hide();
 	m_restoreBtn->hide();
+	m_closeBtn->show();
 
 	const int rightSpace = 3;
 	const int buttonGap = 1;
@@ -403,5 +408,17 @@ void SubWindow::resizeEvent( QResizeEvent * event )
 	}
 }
 
+QPushButton* SubWindow::addTitleButton(const std::string & iconName, const QString & toolTip)
+{
+	auto button = new QPushButton(embed::getIconPixmap(iconName), QString(), this);
+	button->resize(m_buttonSize);
+	button->setFocusPolicy(Qt::NoFocus);
+	button->setCursor(Qt::ArrowCursor);
+	button->setAttribute(Qt::WA_NoMousePropagation);
+	button->setToolTip(toolTip);
+
+	return button;
+}
+
 
-} // namespace lmms::gui
+} // namespace lmms::gui

src/gui/instrument/InstrumentTrackWindow.cpp

@@ -285,24 +285,30 @@ InstrumentTrackWindow::InstrumentTrackWindow( InstrumentTrackView * _itv ) :
 
 	QMdiSubWindow* subWin = getGUI()->mainWindow()->addWindowedWidget( this );
 	Qt::WindowFlags flags = subWin->windowFlags();
-	if (!m_instrumentView->isResizable()) {
-		flags |= Qt::MSWindowsFixedSizeDialogHint;
-		// any better way than this?
-	} else {
-		subWin->setMaximumSize(m_instrumentView->maximumHeight() + 12, m_instrumentView->maximumWidth() + 208);
-		subWin->setMinimumSize( m_instrumentView->minimumWidth() + 12, m_instrumentView->minimumHeight() + 208);
+
+	if (m_instrumentView->isResizable())
+	{
+		// TODO As of writing SlicerT is the only resizable instrument. Is this code specific to SlicerT?
+		const auto extraSpace = QSize(12, 208);
+		subWin->setMaximumSize(m_instrumentView->maximumSize() + extraSpace);
+		subWin->setMinimumSize(m_instrumentView->minimumSize() + extraSpace);
+
+		flags |= Qt::WindowMaximizeButtonHint;
 	}
-	flags &= ~Qt::WindowMaximizeButtonHint;
-	subWin->setWindowFlags( flags );
+	else
+	{
+		flags |= Qt::MSWindowsFixedSizeDialogHint;
+		flags &= ~Qt::WindowMaximizeButtonHint;
 
+		// Hide the Size and Maximize options from the system menu since the dialog size is fixed.
+		QMenu * systemMenu = subWin->systemMenu();
+		systemMenu->actions().at(2)->setVisible(false); // Size
+		systemMenu->actions().at(4)->setVisible(false); // Maximize
+	}
 
-	// Hide the Size and Maximize options from the system menu
-	// since the dialog size is fixed.
-	QMenu * systemMenu = subWin->systemMenu();
-	systemMenu->actions().at( 2 )->setVisible( false ); // Size
-	systemMenu->actions().at( 4 )->setVisible( false ); // Maximize
+	subWin->setWindowFlags(flags);
 
-	subWin->setWindowIcon( embed::getIconPixmap( "instrument_track" ) );
+	subWin->setWindowIcon(embed::getIconPixmap("instrument_track"));
 	subWin->hide();
 }